Torrential downpours claimed a second victim yesterday in Devon as emergency medical supplies and food parcels were sent to communities marooned by floods in Cumbria, and rescue teams searched the swollen river Usk in Wales for a missing woman.

Hundreds of police, soldiers and volunteers were in action along Britain's western seaboard, as a second slow-moving weather front unloaded hours' more rain from Dartmoor to the Scottish border, with even more expected this week.

Engineers are examining 1,800 bridges in Cumbria, where six have collapsed after the floods on the rivers Cocker and Derwent, which meet at Cockermouth. The county council estimates that at least £75m of damage was done to property and infrastructure, with detailed surveys likely to take weeks to reach a final bill. The eventual insurance bill for Cumbria could reach £100m.

The port of Workington, already inundated by Thursday's record downpour, was cut in half when a crack in the central arch of Calva bridge widened to 15cm and the road slumped by 30cm. Hundreds of people have been left stranded on the Northside housing estate, where the area's Labour MP, Tony Cunningham, appealed for food and medical supplies.

A canoeist died after being trapped under a fallen tree on the river Dart in Devon. Chris Wheeler's body was recovered after a mountain rescue team had trekked for two hours through storms.

Two inshore rescue craft were launched on the Usk near Brecon after witnesses saw a woman being swept away by floodwater. A Sea King helicopter and dog teams joined the search, while other RAF helicopters remained on alert near Workington and Cockermouth, whose main street finally emerged from 2.5 metre floods, littered with smashed trees, abandoned cars and ruined goods from local shops.

Military Bailey bridges are likely to be installed temporarily to relieve Northside, where Cunningham said the police station was out of action and the medical centre was down to its last nappies and other supplies. He said: "Until we can get bridges, people are having to take a 90-mile round trip to reach their former neighbours."

Canon Bryan Rowe, of St Michael's Church in Workington, said: "We are isolated. We are a long way from a motorway now. We can't even go to the other side of the river. It's going to take months to put right. But you won't hear any twining [Cumbrian dialect for moaning]. Nnobody is going, 'Woe is us', everybody is just trying to help somebody else."

Police taped off the centre of Cockermouth yesterday, as 13 buildings were declared in imminent danger of collapse and engineers struggled to restore street lighting in pouring rain. About 60 people remain at emergency centres in the town and Workington, but more than 250 are staying with friends, relatives or at hotels and B&Bs, most of them unlikely to return home before Christmas.

The speed and strength of the flood tore down a 3 metre wall round the front garden of Wordsworth's birthplace in Cockermouth, and although the handsome Georgian townhouse is intact, no one is being allowed access because of possible structural problems. The town's statue of the sixth Earl of Mayo, which surveys the centre of Main Street, survived on its pedestal, as did the Christmas tree.

"We are determined to pick ourselves up as much as we can in time for Christmas," said local town and county councillor Eric Nicholson. Hospital manager Chris Holland, helping police direct traffic as a Churches Together in Cumbria volunteer, said: "We want to get the band to play in the centre, sort out the Christmas tree and lay something on as soon as it's practicable."Debris was being cleared from the town and Workington yesterday afternoon, and a lone pheasant stalking Cockermouth's Main Street had to look hard for remains of groceries swept from a local deli.

The Association of British Insurers estimated the insurance bill in Cumbria at £100m. More than 500 claims have already been received and processing will take place urgently, the organisation said. The government has promised an extra £1m emergency reconstruction aid, matching a pledge from the North West regional development association.

Proposals are gathering pace to rename the replacement for Workington's vanished Northside bridge after PC Bill Barker, the father of four who was swept into the Derwent while directing traffic away.

The Environment Agency said four severe flood warnings had been issued for Cumbria, though this was later reduced to one. A spokesman said dredging the river at Cockermouth would have made "no difference whatsoever" and that, contrary to some reports, there were no outstanding upgrades due. In the rest of the UK rain and strong winds are set to continue throughout the early part of the week, according to the Met Office. Today the showers will be heaviest in the west.